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Neutron crystallographic study of heterotrimeric glutamine amidotransferase CAB
Author(s) -
Li Long,
Adachi Motoyasu,
Yu Jian,
Kato Koji,
Shinoda Akira,
Ostermann Andreas,
Schrader Tobias E.,
Ose Toyoyuki,
Yao Min
Publication year - 2019
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x19000220
Subject(s) - heterotrimeric g protein , neutron diffraction , crystallography , glutamine amidotransferase , chemistry , crystal structure , diffractometer , ammonia , glutamine , biochemistry , amino acid , g protein , receptor
Heterotrimeric glutamine amidotransferase CAB (GatCAB) possesses an ammonia‐self‐sufficient mechanism in which ammonia is produced and used in the inner complex by GatA and GatB, respectively. The X‐ray structure of GatCAB revealed that the two identified active sites of GatA and GatB are markedly distant, but are connected in the complex by a channel of 30 Å in length. In order to clarify whether ammonia is transferred through this channel in GatCAB by visualizing ammonia, neutron diffraction studies are indispensable. Here, GatCAB crystals were grown to approximate dimensions of 2.8 × 0.8 × 0.8 mm (a volume of 1.8 mm 3 ) with the aid of a polymer using microseeding and macroseeding processes. Monochromatic neutron diffraction data were collected using the neutron single‐crystal diffractometer BIODIFF at the Heinz Maier‐Leibnitz Zentrum, Germany. The GatCAB crystals belonged to space group P 2 1 2 1 2 1 , with unit‐cell parameters a = 74.6, b = 94.5, c = 182.5 Å and with one GatCAB complex (molecular mass 119 kDa) in the asymmetric unit. This study represented a challenge in current neutron diffraction technology.